The present disclosure generally relates to a multi-component biocide composition that provides improved protection against mold growth, decay, and termite infestation of wood-based materials. Specifically, the multi-component biocide composition comprises a borate component in combination with an azole component to both inhibit decay fungi such as brown-rot fungi and white-rot fungi, mold fungi, and to resist insect infestation.
While lumber and other wood-based materials derived from trees are not perishable, they are, nevertheless, susceptible to a host of natural destructive forces. These primarily include attack by insects, such as termites, carpenter ants and the like and fungi such as brown-rot (Poria Sp.) and white-rot (Polyporous Sp.) wood decay fungi (Poria placenta), as well as mold fungi. Decay fungi are primarily responsible for deterioration of wood (i.e., loss of structural integrity), while mold fungi grow on the surface of wood and do not affect the wood structure. Rather, mold fungi produce copious amounts of spores and can cause health concerns in both humans and animals. Specifically, decay fungi colonize wood over a period of time when the wood moisture content is above fiber saturation (e.g., approximately 30% (by weight) moisture) and the temperature is between approximately 10° C. and approximately 35° C. Mold growth can occur on the wood surface in 24 to 48 hours under conditions of high humidity (e.g., greater than approximately 30° C.) or when in the presence of free water, such as from a leak or flood. Such fungal growth in residential structures in the U.S. accounts for billions of dollars in damages annually.
The increase in mold growth on indoor wood-based materials in residential structures has further lead to an increase in public concern about indoor air quality and health concerns. To date, moisture management through proper construction practices and site drainage provides the best defense against mold growth.
Furthermore, as noted above, wood-based materials are susceptible to insects in addition to fungal attacks. Various species of insects pose problems for living trees and structural wood. For example, Coptotermes formosanus is a major worldwide pest that, unlike other subterranean termites, can establish colonies that do not touch the ground. These termites and other subterranean termites have cost the U.S. over $2 billon annually in damages to residential structures. As such, numerous measures have been made to protect against such infestations. Specifically, three principal methods have been used in the past to control insect growth on wood-based materials both indoors and outdoors: (1) chemical and physical barriers to prevent attacks; (2) wood preservatives and termiticides used to protect infested and susceptible wood, and (3) destruction of termite colonies by excavation of the nest.
Current treatments, however, have not been found completely satisfactory as many compounds in the treatments are environmentally hazardous, many pose safety risks to humans and animals, and create difficult and expensive disposal problems. This is particularly a problem when the treatment is for indoor use such as in the treatment of wood-based materials designed for residential structures. Furthermore, treatments that are safe for indoor use, for example, borate (termiticide), have not been found effective in controlling mold. Specifically, many mold fungi are inherently resistant to UV rays, the numerous chemicals that have been developed, and even most wood preservatives that have been used as protective treatments.
As such, there continues to be a need for a biocide composition for treating wood-based materials that is effective against mold and decay fungal growth and can also prevent insect infestation. Additionally, it would be advantageous if the biocide composition is suitable for indoor use, that is, the biocide composition is non-toxic, nonvolatile, substantially odorless, and hypoallergenic.